Non-standard UART speeds

Official Hardware Nano Family Nano 33 BLE
1

I'm try to use the Nano 33 BLE to read a vehicle datalink which is a standard serial 8N1 port running at 7812 baud. I'm running the same code between this board and another board, but the other board is getting good data. This one isn't. I suspect that Arduino is NOT using the non-standard baud rate, but rounding to the closest standard rate.

Does arduino's Nano 33 library support Non-standard baud rates?

If not, is there some way I can correct this? Which file would I need to modify to convert from baudrate to the correct register value.

Can I use arduino to read and write nRF registers directly?

Thanks for any help!

2

You may have to look at an alternate software serial solution.

One such HERE.

And Arduino's offering HERE.

Bear in mind many of those libs were meant for AVR so your usage may differ on the new NANO series.

Bob.

3

The hardware supports variable baud rates. This seems like a limitation of the arduino software. Can I set registers directly?

4

Here is the actual fix for this which allows non-standard baud rates with this hardware. I did several google searches, but (somehow) missed this one. It worked perfectly!!

#define UARTE0_BASE_ADDR 0x40002000 // As per nRF52840 Product spec - UARTE
#define UARTE1_BASE_ADDR 0x40028000 // As per nRF52840 Product spec - UARTE
#define UART_BAUDRATE_REG_OFFSET 0x524 // As per nRF52840 Product spec - UARTE

#define UART0_BAUDRATE_REGISTER (*(( unsigned int )(UARTE0_BASE_ADDR + UART_BAUDRATE_REG_OFFSET)))
#define UART1_BAUDRATE_REGISTER ((( unsigned int *)(UARTE1_BASE_ADDR + UART_BAUDRATE_REG_OFFSET)))

#define BAUD7812 0x001FFF7A

UART0_BAUDRATE_REGISTER = BAUD7812; //place this in Setup()

Here is a link to the post that helped me.

I was going to modify nrf52840_bitfields to add my baudrate to the baudrate enumeration (then NRF_UART to use it somehow), but this worked better.

Thanks ballscrewbob for providing a response. Hopefully, this helps someone else or Arduino can make there code more dynamic.

5

Wow Thanks for the follow up.
Karma.

Bob.